Problem: Solve for $q$ : $25 = 5 + q$
Answer: Subtract $5$ from both sides: $ \begin{eqnarray} \\ \hphantom{25 {- 5}} &\hphantom{=}& \hphantom{q} \\ 25 &=& 5 + q \\ \\ {-5} && {-5} \\ \end{eqnarray} $ $ \begin{eqnarray} \\ 25 {- 5} &=& q \\ \end{eqnarray} $ Simplify. $ q = 20$